The present invention relates to a photographic flash device which is an artificial light source in the case of photography and more particularly a photographic flash device capable of easily varying the flash light or beam emission angle from a flash tube.
Of the photographic flash devices of the type described, a type wherein various transparent panels such as wide, standard, telescope and so on are detachably mounted on the front face of a flash section comprising a flash tube which flashes by the energy charged on a main discharge capacitor and a reflector and a type wherein the position from the front face of the flash section of a single transparent panel is variable so that wide-angle, standard and telescope lenses may be used with a camera for photography are used in practice.
As compared with the former type, the latter type wherein the position of the single transparent panel is variable has a feature that the flash light emission angle may be readily varied by a single operation. However, in the case of photography it is needed to obtain the exposure data. For instance, in the case of a flash device wherein an automatic flash emission control is possible, this exposure data is such that a distance range in which flash exposures are possible (to be referred to as "the flash exposure range" in this application) is read out when the flash light emission angle is variable with respect to the film speed that is used and the aperture of the camera that is set.
These reading operations are extremely difficult for beginners so that erratic readings result.